public class Example3_1 {
public static void main(String atgs []) {
    char a1 = '十',a2 = '点',a3 = '进',a4 = '攻';
    char secret = 'A';
    a1 = (char)(a1^secret);
a2 = (char)(a2^secret);
a3 = (char)(a3^secret);
a4 = (char)(a4^secret);
System.out.println("密文:"+a1+a2+a3+a4);
a1 = (char)(a1^secret);
a2 = (char)(a2^secret);
a3 = (char)(a3^secret);
a4 = (char)(a4^secret);
System.out.println("原文:"+a1+a2+a3+a4);
    }
}
